| US 7,550,368 B2 | ||
| Group-III nitride semiconductor stack, method of manufacturing the same, and group-III nitride semiconductor device | ||
| Hideto Sugawara, Kanagawa-ken (Japan); and Tsunenori Hiratsuka, Kanagawa-ken (Japan) | ||
| Assigned to Kabushiki Kaisha Toshiba, Tokyo (Japan) | ||
| Filed on May 24, 2006, as Appl. No. 11/439,579. | ||
| Application 11/439579 is a division of application No. 10/806681, filed on Mar. 23, 2004, granted, now 7,148,518. | ||
| Claims priority of application No. 2003-79387 (JP), filed on Mar. 24, 2003. | ||
| Prior Publication US 2006/0223288 A1, Oct. 05, 2006 | ||
| Int. Cl. H01L 21/36 (2006.01); H01L 21/20 (2006.01) | ||
| U.S. Cl. 438—478 [438/46; 438/47; 257/E21.085; 257/E21.097; 257/E21.126; 257/E21.155] | 17 Claims |
| 1. A method of manufacturing a group-III nitride semiconductor stack, comprising:
forming a first group-III nitride layer;
forming a graded low-temperature deposited layer in which group-III element composition is continuously changed, on the first
group-III nitride layer by continuously changing growth temperatures without growth interruption; and
forming a second group-III nitride layer on the graded low-temperature deposited layer without growth interruption,
wherein the graded low-temperature deposited layer is continuous with the first and second group-III nitride layers in terms
of composition and represented by a compositional formula AlxGa1-xN in which a composition ratio x increases from 0, becomes a maximum in the graded low-temperature deposited layer, decreases
again, and becomes 0 at an uppermost portion of the graded low-temperature deposited layer along a direction of growth of
films on the first group-III nitride layer.
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